Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for 3C 273: 12-09 (52), 12-10 (52), 12-08 (50), 12-07 (49), 12-06 (46) — by astronomy; check the weather when the night is within four days.

2027-11-16astronomy score per night — click a bar for that night2027-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-16 Tue	7	—	unknown	04:55–05:40 (marginal, 0.75 h)	50.2° 09:05	10.98	90%	95.3°
2027-11-17 Wed	6	—	unknown	04:55–05:40 (marginal, 0.75 h)	50.2° 09:05	11.01	83%	81.3°
2027-11-18 Thu	6	—	unknown	04:55–05:40 (marginal, 0.75 h)	50.2° 09:00	11.04	73%	67.3°
2027-11-19 Fri	7	—	unknown	04:50–05:40 (marginal, 0.83 h)	50.2° 08:55	11.06	63%	53.3°
2027-11-20 Sat	9	—	unknown	04:45–05:40 (marginal, 0.92 h)	50.2° 08:50	11.09	51%	39.5°
2027-11-21 Sun	12	—	unknown	04:35–05:45 (marginal, 1.17 h)	50.2° 08:45	11.11	40%	26.1°
2027-11-22 Mon	15	—	unknown	05:15–05:45 (good, 0.5 h)	50.2° 08:45	11.14	29%	14.0°
2027-11-23 Tue	20	—	unknown	05:00–05:45 (good, 0.75 h)	50.2° 08:40	11.16	20%	9.8°
2027-11-24 Wed	24	—	unknown	04:55–05:45 (good, 0.83 h)	50.2° 08:35	11.19	12%	19.3°
2027-11-25 Thu	28	—	unknown	04:45–05:45 (good, 1.0 h)	50.2° 08:30	11.21	6%	31.8°
2027-11-26 Fri	29	—	unknown	04:40–05:50 (good, 1.17 h)	50.2° 08:30	11.23	2%	44.7°
2027-11-27 Sat	31	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:25	11.25	0%	57.6°
2027-11-28 Sun	33	—	unknown	04:35–05:50 (good, 1.25 h)	50.2° 08:20	11.27	1%	70.3°
2027-11-29 Mon	35	—	unknown	04:30–05:50 (good, 1.33 h)	50.2° 08:15	11.29	3%	82.8°
2027-11-30 Tue	36	—	unknown	04:25–05:50 (good, 1.42 h)	50.2° 08:10	11.31	8%	95.0°
2027-12-01 Wed	38	—	unknown	04:20–05:55 (good, 1.58 h)	50.2° 08:10	11.33	14%	107.0°
2027-12-02 Thu	40	—	unknown	04:15–05:55 (good, 1.67 h)	50.2° 08:05	11.34	21%	118.8°
2027-12-03 Fri	42	—	unknown	04:15–05:55 (good, 1.67 h)	50.2° 08:00	11.36	29%	130.5°
2027-12-04 Sat	44	—	unknown	04:10–05:55 (good, 1.75 h)	50.2° 07:55	11.38	38%	142.0°
2027-12-05 Sun	45	—	unknown	04:05–05:55 (good, 1.83 h)	50.2° 07:50	11.39	47%	153.2°
2027-12-06 Mon	46	—	unknown	04:00–05:55 (good, 1.92 h)	50.2° 07:50	11.4	57%	163.9°
2027-12-07 Tue	49	—	unknown	04:00–06:00 (good, 2.0 h)	50.2° 07:45	11.42	66%	170.6°
2027-12-08 Wed	50	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:40	11.43	75%	165.3°
2027-12-09 Thu	52	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:35	11.44	83%	154.2°
2027-12-10 Fri	52	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:35	11.45	90%	141.6°
2027-12-11 Sat	46	—	unknown	03:50–06:00 (good, 2.17 h)	50.2° 07:30	11.46	96%	128.4°
2027-12-12 Sun	43	—	unknown	03:55–06:00 (good, 2.08 h)	50.2° 07:25	11.47	99%	114.6°
2027-12-13 Mon	35	—	unknown	04:05–06:00 (good, 1.92 h)	50.2° 07:20	11.48	100%	100.5°
2027-12-14 Tue	28	—	unknown	05:30–06:05 (good, 0.58 h)	50.2° 07:15	11.48	98%	86.1°
2027-12-15 Wed	22	—	unknown	03:20–06:05 (marginal, 2.75 h)	50.2° 07:15	11.49	93%	71.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-16&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.